1. Field of the Invention:
Reverse cycle heat pumps containing a suction line heat exchanger which is operative only during the heating cycle to re-evaporate excess liquid refrigerant carried by the lubricant as it flows to the compressor suction inlet.
2. Description of the Prior Art:
In U.S. Pat. No. 3,077,086, an oil distillation apparatus is provided for a reverse cycle heat pump. A mixture of refrigerant and oil is bled off from the discharge side of the low side refrigerant pump, said mixture being pumped through an oil still which is heated by compressor discharge gas. Since discharge gas, rather than high pressure refrigerant liquid, is used to provide heat for distillation, and the heat exchanger is utilized on both the heating and cooling cycles, the present invention is easily distinguished therefrom.
In U.S. Pat. No. 3,246,482 a heat exchanger is located between the liquid refrigerant line and the suction line; but this is operative during both the heating and cooling cylces of operation. Many similar patents are related to designs which are purposely charged with sufficient refrigerant to maintan a liquid level in the accumulator during both the heating and cooling cycles of operation. Consequently, these require heat exchange for both cycles of operation in order to evaporate liquid returning in the suction line from the accumulator.